git describe candidate filtering

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Would it be possible to add an option to git-describe that limits the
candidate tags to those matching a glob pattern or regular expression?
I've got a repository imported from CVS which has a number of less
interesting tags for events such as branch creation, but I'm only
interested in describing the current commit relative to tags matching
v[0-9]\.[0-9]*, rather than the closest tag of any spelling.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             ebb9@byu.net
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFHYMJQ84KuGfSFAYARAsd8AKCwuCZsxZBcV3nd849Saxvch/OZiACfagTe
mitsZEVhXy7hyBg0KALQG0o=
=Qq8n
-----END PGP SIGNATURE-----

Eric Blake [off-list ref] wrote:

Would it be possible to add an option to git-describe that limits the
candidate tags to those matching a glob pattern or regular expression?
I've got a repository imported from CVS which has a number of less
interesting tags for events such as branch creation, but I'm only
interested in describing the current commit relative to tags matching
v[0-9]\.[0-9]*, rather than the closest tag of any spelling.

Sure, it shouldn't be too difficult, just need to alter the get_name()
function to add the item with add_to_known_names() only if it matches
the pattern.  Take a look at builtin-describe.c around line 74...

We only match things that were "added".  So if you don't add a tag
via add_to_known_names() then git-describe won't return it.

However that's only true for the standard case; for --contains its
a different story as we are actually passing everything to name-rev.

-- 
Shawn.